Tapped insert for cylindrical bore and installation equipment for such insert

ABSTRACT

The present invention relates to a tapped insert for cylindrical plain bore ( 30 ) of a part A 1  comprising a cylindrical body ( 10 ), characterized in that said cylindrical body ( 10 ) comprises an inner bore ( 11 ) of frusto-conical shape, and at least one longitudinal slot ( 12, 12 ′) extending into the cylindrical body ( 10 ) and communicating with said frusto-conical inner bore ( 11 ) and characterized in that the tapped insert also comprises a core ( 20 ) of frusto-conical shape complementary with said frusto-conical inner bore ( 11 ) of the cylindrical body ( 10 ), said core ( 20 ) comprising a inner tapped aperture ( 21 ), said cylindrical body ( 10 ) and said core ( 20 ) being such that said tapped insert can be holded in position and locked in said cylindrical bore ( 30 ) to equip said cylindrical bore with an inner taping.

The present invention relates to a tapped insert for cylindrical bore.

It also concerns installation equipment for such tapped insert.

Generally, the present invention is applicable to the mechanical linkingdomain of screw-nut type and more especially concerns the making of thefemale thread part of the mechanical link by means of a tapped insert.

The simplification of the machining in a part of a cylindrical boreintended to accommodate an attaching screw is known by using a tappedinsert to ensure the function of the nut of an attachment system, byscrewing. The cylindrical bore can thus be limited to a simple drillingoperation.

Such tapped insert is especially used in a non-exhaustive manner to makemechanical screw-nut links in blind bores or, again, where overall size,material or, again, sealing problems exist allowing access via only oneside of the part.

Various types of tapped inserts are known to ensure the internal tappingfunction in a plain bore.

For example, the use of a cylindrical insert with a knurled outsidesurface and a tapped inside surface corresponding to the thread of anattachment screw is known.

However, after insertion of an insert in a bore, the removal of saidinsert is generally impossible without destroying the insert or damagingthe bore.

It is an object of the present invention to solve the above-mentioneddisadvantages and to propose a tapped insert for cylindrical bore,simple to install and replace, without damaging the cylindrical bore orthe tapped insert.

For this purpose, the present invention relates according to a firstaspect to a tapped insert for cylindrical plain bore of a partcomprising a cylindrical body.

According to the invention, the cylindrical body comprises an inner boreof frusto-conical shape and at least one longitudinal slot extending inthe cylindrical body and communicating with said frusto-conical innerbore, said tapped insert also comprising a core having a frusto-conicalshape complementary to said frusto-conical inner bore of the cylindricalbody, said core comprising an inner tapped aperture, said cylindricalbody and said core being such that said tapped insert can be holded inposition and locked in said cylindrical bore to equip said cylindricalbore with an inner taping.

Thus, thanks to the core of frusto-conical shape inserted into acomplementary bore of the slotted cylindrical body, it is possible toobtain by displacement of the core in the frusto-conical inner bore acontrolled deformation of the slotted cylindrical body in its diameterthus holding the tapped insert in position in a cylindrical bore.

By modifying the position of the core of frusto-conical shape in thefrusto-conical inner bore of the cylindrical body, the anchoring forceof the tapped insert in the cylindrical bore can be adjusted in such away that the maximum allowable axial force during the screwing of ascrew into the tapped insert can also be adjusted.

Moreover, the anchoring by positioning of the core of frusto-conicalshape in the frusto-conical inner bore of the cylindrical body isreversible so that the replacement of the tapped insert can be easilyobtained without its destruction or damage to the cylindrical bore.

The value of the half-angle of the core of frusto-conical shape and ofthe frusto-conical inner bore and the friction coefficient between thecylindrical bore to be equipped in said part and the cylindrical bodyare chosen to guarantee locking of said tapped insert.

In one embodiment, the half-angle value of the core of frusto-conicalshape is comprised between 2.5° and 5°.

Preferentially, the diameter of the large base of said core offrusto-conical shape is substantially greater than or equal to thediameter of the large base of the frusto-conical inner bore of saidcylindrical body.

During the displacement of the core of frusto-conical shape in thefrusto-conical inner bore of the cylindrical body, the deformation ofthe cylindrical body is especially obtained by deforming the cylindricalbody by diametral expansion.

To ensure a high expansion of the tapped insert if necessary, thecylindrical body comprises preferentially several slots extending over apart of the length of the cylindrical body and communicating with thefrusto-conical inner bore.

According to an advantageous embodiment of the invention, saidcylindrical body comprises a collar protruding from the outer wall ofsaid cylindrical body, extending in the plane of a proximal face of saidtapped insert, opposite to the large base of said frusto-conical innerbore of the cylindrical body.

The protruding collar ensures the longitudinal positioning of the insertin the cylindrical bore by the collar coming into contact with a face ofa part with which the cylindrical bore to be equipped communicates.

According to one embodiment, the surface of the outer wall of saidcylindrical body is structured, and preferentially knurled or striated.

According to another embodiment of the invention, said cylindrical bodyalso comprises a tapped inner wall portion at one end of saidfrusto-conical inner bore, opposite the large base of saidfrusto-conical inner bore.

The present invention also relates according to a second aspect totapped insert installation and removal equipment for a cylindrical bore.

This installation and removal equipment comprises at least one tappedinsert according to the first aspect of the invention, the cylindricalbody also comprising a tapped inner wall portion at one end of thefrusto-conical inner bore, opposite the large base of the frusto-conicalinner bore, and a tapped insert installation and removal tool.

This installation and removal tool comprises:

-   -   a cylindrical body comprising a threaded end section, the thread        of said end portion being adapted to the tapping of said tapped        inner wall portion of the cylindrical body of said tapped        insert, said cylindrical body of the tool comprising an inner        tapping, and    -   a screw of diameter substantially lower than the diameter of        said inner bore of the cylindrical body of the tool, said screw        comprising at one end a complementary thread of the inner tapped        aperture of the core of said tapped insert.

The threaded end portion of the tool thus allows the cylindrical body ofthe tapped insert to be held fixed in a determined position when thescrew is screwed into the inner tapped aperture of the core thusenabling the longitudinal displacement of the core in the cylindricalbody and the expansion of the latter in the bore to be equipped.

Preferentially, the installation and removal tool also comprises apositioning ring installed to slide on said cylindrical body of saidtool, said cylindrical body and said positioning ring comprisingcomplementary sliding means adapted to hold said positioning ring onsaid cylindrical body in a defined longitudinal transverse section.

This positioning ring thus allows the depth at which the tapped insertis positioned by the installation and removal tool to be defined in thecylindrical bore to be equipped.

The insert can thus be positioned in an accurate and reproducible way inthe cylindrical bore at a given depth.

The present invention also concerns a method for installing a tappedinsert in a cylindrical bore of a part with said tapped insertinstallation and removal equipment, comprising the following steps:

-   -   screwing said end portion into said tapped inner wall portion of        said cylindrical body;    -   inserting and partially screwing said screw into the tapped        aperture of the core placed in said cylindrical body;    -   adjusting the depth by which said tapped insert will be inserted        into said part;    -   screwing said screw into said tapped insert until obtaining the        required anchoring force;    -   removing said screw and said body.

The depth by which the tapped insert will be inserted in a cylindricalbore of said part is adjusted by moving a positioning ring on thecylindrical body of said equipment, said positioning ring coming intocontact with a front face of said part when said tapped insert isinserted.

The present invention also concerns a method for removing a tappedinsert in a cylindrical bore of a part with said tapped insertinstallation and removal equipment comprising the following steps:

-   -   screwing said end portion into said tapped inner wall portion of        said cylindrical body;    -   moving a positioning ring along said cylindrical body of said        equipment to come into contact with a front face of said part;    -   inserting screw into the tapped inner bore of the core;    -   screwing the screw until leaving a clearance between the head of        the screw and the cylindrical body of the equipment;    -   making a light impact against the screw;    -   removing the tapped insert with the equipment.

Other features and advantages of the invention will become apparent onreading the following description.

On the accompanying drawings, given as non-limitative examples:

FIG. 1A is a perspective view of a tapped insert according to a firstembodiment of the invention;

FIG. 1B is an exploded perspective view of the tapped insert of FIG. 1A;

FIG. 2 is a longitudinal cross-sectional view illustrating theinstallation of a tapped insert in a cylindrical bore according to thefirst embodiment of the invention;

FIG. 3 is a perspective view of a tapped insert according to a secondembodiment of the invention;

FIG. 4 is a perspective view of a tapped insert according to a thirdembodiment of the invention;

FIG. 5 is a perspective view of a tapped insert according to a fourthembodiment of the invention;

FIG. 6 is a longitudinal cross-sectional view of an installation andremoval tool for the tapped insert of FIG. 5;

FIGS. 7A to 7E schematically illustrate the installation on a tappedinsert with the tool of FIG. 6, and

FIGS. 8A to 8E illustrate the removal of an insert with the tool of FIG.6.

A description will first of all be given in reference to FIGS. 1A and 1Bof a first embodiment of a tapped insert according to the invention.

This tapped insert comprises a cylindrical body 10 with a shape adaptedto a cylindrical bore to be equipped.

In practice, the diameter of the cylindrical body 10 is determined sothat it is somewhat smaller than the diameter of the cylindrical bore tobe equipped.

Moreover, the length of the cylindrical body 10 of the tapped insert issubstantially equal to the diameter of the cylindrical bore to beequipped.

As clearly illustrated on FIG. 1B, said cylindrical body 10 includes aninner bore 11 of frusto-conical shape.

As a non-limitative example, the half-angle of the cone defining thefrusto-conical shape of the inner bore 11 is approximately equal to2.5°.

The value of the half-angle of the cone can also be greater than 2.5°whilst preferentially remaining lower than 5°.

The cylindrical body 10 also comprises at least one longitudinal slot,here a single slot 12 extending in the length of the cylindrical body 10and communicating with the frusto-conical inner bore 11.

Preferentially, the width of this longitudinal slot 12 is as low aspossible, determined by the manufacturing constraints of the slottedcylindrical body 10.

Thus, this longitudinal slot 12 extends along a generatrix of thecylindrical body 10, with central longitudinal axis X.

The tapped insert also comprises a core 20 of frusto-conical shapecomplementary to the frusto-conical inner bore 11 of the cylindricalbody 12.

Thus, the core of frusto-conical shape 20 has a frustum of a cone shapewith same half-angle as that of the frusto-conical inner bore 11 of thecylindrical body 10, between 2.5° and 5° and, here, approximately equalto 2.5°.

The length of the core of frusto-conical shape 20 is substantially equalto the length of the cylindrical body 10 in the longitudinal direction.

Moreover, the diameter of the large base 20 a of the core offrusto-conical shape 20 is substantially greater than or equal to thediameter of the large base 11 a of the frusto-conical inner bore 11 ofthe cylindrical body 10.

Thus, the core of frusto-conical shape 20 can be inserted into thefrusto-conical inner bore 11 of the cylindrical body 10 and come intocontact by its large base 20 a with the large base 11 a of thefrusto-conical inner bore 11.

Moreover, the core of frusto-conical shape 20 includes an inner tappedaperture 21.

This inner tapped aperture 21 is of cylindrical shape and extends in thelongitudinal direction of the core of frusto-conical shape 20, of samecentral longitudinal axis X, when the core of frusto-conical shape 20 isinserted into the cylindrical body 10.

Preferentially, as illustrated in this embodiment, the inner tappedaperture 21 communicates on each side with the core of frusto-conicalshape 20.

Moreover, the diameter of the small base 11 b of the frusto-conicalinner bore 11 of the cylindrical body 10 is slightly greater than thediameter of the inner tapped aperture 21 of the core of frusto-conicalshape 20.

A description will now be given in reference to FIG. 2 of theinstallation of such tapped insert in a cylindrical bore.

In the embodiment illustrated on FIG. 2, a cylindrical bore 30 is thusprovided in a part A.

The assembly of the tapped insert is performed as follows.

The core of frusto-conical shape 20 is placed in the slotted cylindricalbody 10, the two elements being in perfect geometrical adequation onaccount of the complementary frusto-conical shapes.

The installation of the tapped insert is done by simply positioning saidinsert in the bore 30 of part A, the diameter of which is very slightlyhigher than the diameter of the cylindrical body 10.

It is to be noted concerning this that the cylindrical bore 30 can becommunicating or not.

In the embodiment illustrated on FIG. 2, the cylindrical bore 30 isblind.

The insert of frusto-conical shape 20 is inserted into thefrusto-conical inner bore 11 via the large base 11 a of saidfrusto-conical inner bore 11 in such a way that the small base 20 a ofthe core of frusto-conical shape 20 is moved in direction of the smallbase 11 b of the frusto-conical inner bore 11 along the centrallongitudinal axis X of the tapped insert, also corresponding to thecentral longitudinal axis X of the cylindrical bore 30 to be equipped.

Moreover, concerning the installation direction, the tapped insert isinserted into the cylindrical bore 30 in such a way that the large base20 a of the core of frusto-conical shape 20 comprises a terminal end ofthe tapped insert thus positioned.

Thanks to the inner tapped aperture 21 of the core of frusto-conicalshape 20, a traction force can be exerted on this core of frusto-conicalshape 20 by means of an installation screw 40 the thread 41 of which isadapted to the tapping of the inner tapped aperture 21 during therotation of the installation screw 40.

Thus, with the cylindrical body 10 held in position in the cylindricalbore 30, the traction force exerted by the installation screw 40 on thecore of frusto-conical shape 20 causes the translation movement of thecore of frusto-conical shape 20 in the frusto-conical inner bore 11 ofthe slotted cylindrical body 10.

Once contact has been made between the core of frusto-conical shape 20and the frusto-conical inner bore 11, the traction force in thedirection of arrow F exerted on the core of frusto-conical shape 20causes an increase in the contact pressure between the core offrusto-conical shape 20 and the cylindrical body 10 which leads to thedeformation of said cylindrical body 10.

This deformation is reflected by an expansion of the diameter of thecylindrical body 10 thanks to the presence of the longitudinal slot 12.

This diametral expansion of the cylindrical body 10 will fill the smallclearance existing between the initial diameter of the cylindrical body10 and the diameter of the cylindrical bore 30 to be equipped.

Thus, the elimination of this clearance leads to the locking of thetapped insert in the cylindrical bore 30.

It is to be noted that the lower the difference in diameter between thecylindrical bore 30 and the cylindrical body 10, the more thedeformation of the slotted cylindrical body 10 can be limited.

Moreover, once the cylindrical body 10 is in contact with thecylindrical bore 30 of part A, an additional locking force may berequired to ensure the correct anchoring of the tapped insert in thecylindrical bore 30.

Concerning this, it is to be noted that a direct relation exists betweenthe traction force exerted by the installation screw 40 and the maximumaxial force to which the tapped insert can be submitted once positioned.

The tightening torque exerted on the installation screw 40 can thus bemeasured, for example by a torque wrench, to adjust the maximum axialforce liable to be supported by the tapped insert.

It is to be noted that a direct relation exists between the tractionforce exerted by the installation screw 40 and the contact pressurebetween the core of frusto-conical shape 20 and the cylindrical body 10.

Thus, the maximum axial traction force that the tapped insert cansupport varies according to the value of the half-angle of the core offrusto-conical shape 20 and of the frusto-conical inner bore 11 and thefriction coefficient between the cylindrical bore 30 to be equipped inpart A and the cylindrical body 10 (depending on the materials used forthe part A and the cylindrical body 10).

For a half-angle value of the core of frusto-conical shape of comprisedbetween 2.5° and 5°, all materials, metallic or non-metallic, can beused to make the tapped insert and guarantee locking of the tappedinsert in the cylindrical bore 30 to be equipped.

Once the tapped insert is locked in the cylindrical bore 30, theinstallation screw 40 can be removed to leave the tapped insert inposition for its later use.

This tapped insert thus allows a plain cylindrical bore to be equippedwith an inner tapping.

Now, a tapped insert in accordance with a second embodiment of theinvention will be described in reference to FIG. 3.

This tapped insert is from all points of view identical to the onedescribed previously in reference to FIGS. 1A and 1B, the commonelements having the same references.

However, this tapped insert also comprises, on the cylindrical body 10,a collar 13 protruding from the outer wall 10′ of the cylindrical body10.

Here, this collar 13 has a annular shape concentric with the cylindricalbody 10, with same central longitudinal axis X.

This collar 13 extends protruding in the plane of the proximal face ofthe tapped insert, opposite the large base 11 a of the frusto-conicalinner bore 11 of the cylindrical body 10.

Thus, this collar 13 extends in the plane into which the small base 11 bof the frusto-conical inner bore 11 of the cylindrical body 10 extends.

The collar 13 thus enables positioning in abutment for the installationof the insert in a cylindrical bore.

In practice, the cylindrical bore communicating with a front face of apart, the collar 13 of the tapped insert comes into abutment with thisfront face when the cylindrical body 10 is inserted into the cylindricalbore to be equipped.

This collar 13 thus allows the tapped insert to be perfectly positionedin the cylindrical bore 30 and also the cylindrical body to be held inposition during the traction force exerted by an installation screw onthe core of frusto-conical shape 20.

Of course, the collar 13 can have a shape different from an annularshape and, for example, be limited to one or more separate portions,forming flanges protruding from the outer wall 10′ of the cylindricalbody 10.

FIG. 4 illustrates a third embodiment substantially identical to the onedescribed previously in reference to FIG. 3.

In this third embodiment, the cylindrical body 10 comprises severallongitudinal slots 12, 12′.

Preferentially, when the cylindrical body comprises several longitudinalslots 12, these are equally distributed angularly on the outer wall 10′of the cylindrical body to obtain a uniform deformation of thecylindrical body 10 during the expansion of its diameter in thecylindrical bore to be equipped.

The presence of several longitudinal slots 12, 12′ in the cylindricalbody 10 also allows the expansion capability of the cylindrical body inthe cylindrical bore to be increased.

Now, a fourth embodiment of the tapped insert according to the inventionwill be described in reference to FIG. 5.

This fourth embodiment of the invention is substantially identical tothe one described previously in reference to FIGS. 1A and 1B, the commonelements having the same numerical references.

Here, to improve the anchoring of the tapped insert in the cylindricalbore, especially when the part comprising the cylindrical bore is madefrom a soft material, the cylindrical body 10 comprises an outer wall10′ with a structured surface and, for example, knurled or striated.

Unlike a plain surface, the structuring of the surface of the outer wall10′ of the cylindrical body 10 allows the anchoring to be improved andthus the holding in position of the tapped insert in the cylindricalbore to be equipped.

Moreover, in this fourth embodiment, the cylindrical body 10 comprises atapped inner wall portion 14 at one end of the frusto-conical innerbore, opposite the large base 11 a of the frusto-conical inner bore 11.

The cylindrical body 10 thus comprises a tapped inner wall portion 14,defining a cylindrical inner bore portion, joined at the small base 11 bto the frusto-conical inner bore 11.

As will be described below, said tapped inner wall 14 advantageouslyallows the use of an installation and removal tool for such insert tohold the cylindrical body 10 in position in the cylindrical bore to beequipped.

In this embodiment, the core of frusto-conical shape 20 has then alength somewhat lower than the length of the cylindrical body 10 so thatit can be accommodated in the part of the frusto-conical inner bore 11extending beyond the tapped inner wall 14 of the cylindrical body 10.

Now, the installation and removal tool for the tapped insert asillustrated on FIG. 5 will be described in reference to FIG. 6.

This installation and removal tool 50 comprises a cylindrical body 51comprising at least one threaded end portion 52.

As can be clearly seen on FIG. 6, the thread of this end portion 52 isadapted to the dimensions of the tapping of the tapped inner wallportion 14 of the cylindrical body 10.

It is thus to be noted that the cylindrical body 51 of the installationand removal tool 50 can be screwed into the tapped inner wall portion 14of the cylindrical body 10 of the tapped insert.

The cylindrical body 51 and its threaded end 52 must of course have anominal diameter lower than the diameter of the cylindrical bore to beequipped.

The cylindrical body 51 of the installation and removal tool 50 alsocomprises an inner bore 53 and a screw 55 of diameter substantiallylower than the diameter of the inner bore 53 of the cylindrical body 51of the installation and removal tool 50.

This screw 55 comprises at one end 55 a a thread complementary to thetapped inner aperture 21 of the core of frusto-conical shape 20 of thetapped insert.

This screw 55 has a sufficient length to pass through the cylindricalbody 51 of the tool and protrude beyond the threaded end portion 52 tobe inserted into the tapped inner aperture 21 of the core offrusto-conical shape 20.

Moreover, in this embodiment, and in an in no way limitative manner, apositioning ring 60 is installed so as to slide on the cylindrical body51 of the tool 50.

Generally, the cylindrical body 51 and the positioning ring 60 comprisecomplementary sliding means adapted to enable the relative sliding ofthe positioning ring 60 on the cylindrical body 51 and the maintainingof this positioning ring 60 on the cylindrical body 51 in a definedtransverse section of the cylindrical body 51 of the installation andremoval tool 50.

In this embodiment, the complementary sliding means are ensured thanksto an external thread on the cylindrical body 51 and a correspondinginternal tapping of the positioning ring 60.

Thus, the rotation of the positioning ring 60 around the cylindricalbody 51 causes the longitudinal displacement of this positioning ring 60along the cylindrical body 51 of the installation and removal tool 50.

The existence of the complementary thread between the positioning ring60 and the cylindrical body 51 automatically enables said positioningring 60 to be maintained in translation in a defined transverse sectionof the cylindrical body 51.

Now, the installation of a tapped insert of FIG. 5 thanks to theinstallation and removal tool 50 described previously will be describedin reference to FIGS. 7A to 7E.

The threaded end 52 is installed by screwing into the tapped inner wallportion 14 of the cylindrical body 10 of the tapped insert and the screw55 of the tool is inserted and partially screwed into the tapped inneraperture 21 of the core of frusto-conical shape 20 placed in thefrusto-conical inner bore 11 of the cylindrical body 10 of the tappedinsert.

Dimension C, corresponding to the depth by which the tapped insert willbe inserted into a cylindrical bore 30 of part A, is then adjusted bymoving the positioning ring 60 on the cylindrical body 51 of the tool asillustrated on FIG. 7A.

The adjustment of this dimension C is thus done by screwing orunscrewing the positioning ring 60 on the cylindrical body 51 of thetool 50.

As illustrated on FIG. 7B, the assembly is then inserted into thecylindrical bore 30, the insertion movement being limited by thepositioning ring 60 coming into abutment with a front face of part A,with which the cylindrical bore 30 communicates.

The screw 55 of the tool is then screwed into the tapped insert asillustrated on FIG. 7C to exert, as described previously, a tractionforce on the core of frusto-conical shape 20, according to arrow F, andcause the deformation of the cylindrical body 10 of the tapped insertagainst the inner walls of the cylindrical bore 30.

The screw 55 is thus tightened according to the torque according to therequired anchoring force.

As illustrated on FIG. 7D, the tool is then removed by untightening thescrew 55, then unscrewing the body 51 installed at its threaded end 52into the tapped inner wall portion 14 of the cylindrical body 10.

The tapped insert is then positioned in the cylindrical bore 30 of partA as illustrated on FIG. 7E.

Now, the removal of such insert, from its position in the cylindricalbore 30 as illustrated on FIG. 8A, will be described in reference toFIGS. 8A to 8E.

First of all, as illustrated on FIG. 8B, the installation and removaltool 50 is installed by screwing of the threaded end 52 into the tappedinner wall portion 14 of the cylindrical body 10.

The positioning ring 60 is then moved along the cylindrical body 51 ofthe tool to come into contact with the front face of part A.

The screw 55 is then inserted into the tapped inner bore 21 of the coreof frusto-conical shape 20.

This screw 55 is screwed in until a clearance J is left between the head55 b of the screw 55 and the cylindrical body 51 of the installation andremoval tool 50.

As illustrated on FIG. 8C, by making a light impact in the direction ofarrow G against the head 55 b of screw 55, the core of frusto-conicalshape 20 is moved in translation into the frusto-conical inner bore 11of the cylindrical body 10 of the tapped insert, in the direction of thelarge base 11 a of said frusto-conical inner bore 11.

The pressure exerted by this insert of frusto-conical shape 20 on thecylindrical body 10 is thus eliminated thanks to the backward movementof the core of frusto-conical shape 20 in the direction (arrow G) of theforce exerted on the screw 55.

The installation and removal tool can then be removed with the tappedinsert attached to the threaded end 55 a of the screw 55.

This removal of the tapped insert installed on the screw 55 insertedinto the cylindrical body 51 of the tool can also be obtained byscrewing the positioning ring 60 against the front face of part A asillustrated on FIG. 8D.

Indeed, the screwing of this positioning ring 60, held in abutmentagainst the front face of the part A, leads to the relative movement,according to arrow H, of the complete cylindrical body 51 of theinstallation and removal tool 50.

As illustrated on FIG. 8E, we thus obtain the removal of the tappedinsert from the cylindrical bore 30 of the part A.

Thus, the positioning and the removal of the tapped insert can be donewithout damaging the cylindrical bore 30.

The replacement of the tapped insert can thus be easily achieved thanksto the installation and removal tool.

Of course, the present invention is not limited to the embodimentexamples described above.

In particular, the various characteristics described in relation to thevarious embodiments can be combined in a variable manner.

Thus, in particular, the tapped insert with several slots illustrated onFIG. 4 may not have a collar.

Also, the tapped insert of FIG. 5 usable with the installation andremoval tool can have an outer wall with a plain surface.

However, it is to be noted that during the use of an installation andremoval tool allowing the tapped insert to be positioned at a determineddepth in a cylindrical bore, said tapped insert is not equipped with acollar intended to come into abutment with a front face of the part withthe cylindrical bore to be equipped.

The invention claimed is:
 1. A tapped insert for a cylindrical bore in asurface of a part, comprising: a cylindrical body that includes an innerbore of frusto-conical shape, a threaded inner wall portion adjacent tothe frusto-conical inner bore in an axial direction of the cylindricalbody, and at least one longitudinal slot extending into the cylindricalbody and communicating with said frusto-conical inner bore; and a coreof frusto-conical shape complementary with said frusto-conical innerbore of the cylindrical body, said core including an inner threadedaperture, wherein said cylindrical body and said core are configuredsuch that said tapped insert can be held in position and locked in saidcylindrical bore of the part, wherein the cylindrical body has a firstend configured to be distal from the surface of the part and a secondend opposite to the first end in the axial direction of the cylindricalbody, a diameter of the frusto-conical inner bore increases in adirection from the second end to the first end, and a diameter ofthreaded inner wall portion of the cylindrical body is greater than adiameter of inner threaded aperture of the core.
 2. The tapped insertaccording to claim 1, wherein a value of a half-angle of the core offrusto-conical shape and of the frusto-conical inner bore and a frictioncoefficient between the cylindrical bore of the part and the cylindricalbody are chosen to lock said tapped insert in the cylindrical bore. 3.The tapped insert according to claim 2, wherein the half-angle value ofthe core of frusto-conical shape is comprised between 2.5° and 5° . 4.The tapped insert according to claim 1, wherein said cylindrical bodycomprises a collar protruding from an outer wall of said cylindricalbody, that is opposite a base of said frusto-conical inner bore of thecylindrical body.
 5. The tapped insert according to claim 1, wherein theat least one longitudinal slot includes a plurality of slots that extendover a part of a length of said cylindrical body and communicating withsaid frusto-conical inner bore.
 6. The tapped insert according to claim4, wherein a surface of the outer wall of said cylindrical body isknurled or striated.
 7. The tapped insert according to claim 4, whereinthe threaded inner wall portion of the cylindrical body is at one end ofsaid frusto-conical inner bore, opposite the base of said frusto-conicalinner bore.
 8. The tapped insert according to claim 1, wherein thediameter of the threaded inner wall portion is greater than a largestdiameter of the frusto-conical inner bore.
 9. The tapped insertaccording to claim 1, wherein the threaded inner wall portion adjacentof the body is at the second end.